  HD
Cable Modification
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Carb End cable mount using stock bracket
Simple substitute
linkage for using Weber IDFs on a waffle top manifold. The cable
is a Harley Davidson motorcycle throttle cable commonly available
from a chopper shop or dealer for only a couple of dollars. Usually
it includes the end nuts and cable stop. Be sure to click on
the pictures for better detail and notes.
Center Cable Pull
Cable
as it goes to the center throttle ball between the two carbs.
--->
Save the bracket
for your mechanical linkage that you removed. It can be used
as the carb. end support for your cable. Simply mount it as shown
on it's original mounting pad on the driver's side cam box. Just
turn it 90 degrees as shown in the picture at left. Loop the
short cable down and between the carbs Fashion an "L"
bracket about 2" from the firewall and run the cable through
it and let the cable cover rest on the bracket. As you pull the
cable the carbs should open.
 Pass the cable through
the hand throttle bracket that sticks up from the throttle pivot
point. This just happens to be the perfect length to open the
carbs. Check your clearances. I had to slightly bend the lever
toward the cam box to get it to align correctly. You will want
to have someone in the car to push the pedal all the way down
as you look down the carbs to see if the butterflies are opening
correctly. Firewall Detail --->
You want to
be doubly sure that there are no possibilities that something
could interfere with correct throttle openings and closings.
BTW, I would not trust the return spring on the IDFs. I mounted,
and suggest that you do to, a second spring from the master cylinder
over to the throttle lever to ensure closure in case of something
unforeseen happening. I also check my installation each year
for fraying wire or loose brackets. So far everything has been
fine, but it's good to know that there are no worries in this
area.
Update
notes
The Cable:
The shortest "chopper" right angle cable is plenty
long, but you may want to pick up a kit as they have the outer
cable end fitting with it's stop and a brass or steel cable clamp
for the other end. I think these go for about $10 or less at
a dirty chopper shop Fog Hollow has a whole wall of new and used
ones here for even less. I believe they are on the net.
The pedal:
The old throttle fitting arm must be bent out of the way. Some
cars will have to have the arm hacksawed off. I've done it both
ways. On my 73, I was able to save the arm and bend it in a way
that it hit the manifold and worked like a "stop" on
the 71 I didn't get away so lucky.
Carb Cable End:
Just a simple loop in the cable tight around the ball with a
metal sleeve is adequate to keep it from sliding over the ball.
Make it tight and it will last forever. Mine is 20 years old
and still going strong.
 Modifications to the firewall:
I have since devised a better stop for the outer cable at the
firewall end. Simply bend a piece of 1" aluminum strap into
a square U shape with a flange at both ends for screws. Looking
in the picture on the right above this update note the U bracket
would mount on the firewall to the right of the shiney cable
stop and would surround the throttle pedal lever catching if
from falling too far to the left.
Make the U shape just long
enough to get from the firewall to where the hand throttle will
rest when the pedal is resting. Funny thing is the throw on the
lever is perfect for the IDF linkage with no modification. The
time to make and install this bracket is before you install the
manifold. It can be done after but you will probably want to
remove the rear carb to get enough access. Presently I have my
L bracket mounted to the rearmost cam box bolt. Works ok and
is easy. I think the U bracket is better.
Drill a hole in the bottom
of the U for the cable to pass through. The hole must be small
enough for the inner cable to pass through but too small for
the outer casing. This gets fastened to the firewall right over
the hand throttle lever. It will function as a pedal stop and
you don't have to fool with rigging something off of the carb
bolts. Those are tough enough already. I did this to another
spider and it works great. The next time I work with Red's cable,
I'm going to upgrade it.
The nice thing about this install
is that it is so clean and pretty much hidden by the aircleaners.
The cable is plenty strong for this application but I do recommend
that you BE SURE THE INSTALLED SYSTEM WORKS FREELY AND YOU
APPLY AN ADDITIONAL SPRING TO ENSURE THE THROTTLE CLOSES.
Mine works ok without it, but for a little more piece of mind
and a little heavier throttle feel, I added a small spring from
the boss on the bottom of the manifold to the throttle ball on
the carbs.
BTW, the bracket that I used
on the intake cam cover for the carb cable end is just the old
bracket from the original throttle linkage. 
Finished installation with factory turtleback aircleaner
covering up all of the clever work
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With after market air cleaners --->
The cable runs
forward then loops around between the intake cam and the carbs
and comes back to the fast idle lever on the throttle lever.
You can create a cable stop from the cam housing, the carb base
(hard to get to) or fabricate a bracket. The bright bolt is the
cable stop. You will have to fabricate a cable stop near the
firewall to use the stock floor pedal. You will also have to
remove the stock carb linkage arm on the engine side of the throttle
lever as it interferers with the intake manifold.The cable came
with the rubber bushing. I highly recommend an extra throttle
return spring just in case. Fabrication and installation time
was about three hours after the original manifold and carb was
removed.
Air Cleaner
elements for the turtleback have been getting hard to find lately,
but thanks to Tom Nicotera, we have some substitutes. These units
are round but are the correct height and length and only need
to be ovaled slightly to fit into the case.
Purolater: A50991 - Fram: CA340A
- WIX: 42113
K&N: E1580 - Amsoil: TS20 - STP: SA340A
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